(Reuters) - Defender Hector Bellerin has struggled to return to his best due to ankle problems and did not deserve the criticism he received after Arsenal's 3-0 loss at Crystal Palace in the Premier League last week, manager Arsene Wenger has said.

Arsenal, who are seventh in the table, trail fourth-placed Manchester City by 10 points with two games in hand and have been heavily criticised in recent weeks after just two wins in their last eight league games.

Bellerin was sidelined for a month in November due to an ankle injury that resurfaced in January causing him to miss Arsenal's FA Cup win over Preston North End and league win over Swansea City.

"I think it's unfair... I agree that for a while he was not the Hector Bellerin we had seen at the start of the season. He has not come back to his level since he has been injured," Wenger told the club's website (www.arsenal.com).

"I think now he is trying to focus on again what is important, to defend well. After he can give us the extra bit (going forward) that is important as well."

Wenger urged his team to respond to the Palace defeat and called for unity between the fans and the club.

"The fans want to be behind the team and the way we respond on the football pitch will decide the attitude of the fans," Wenger said.

"The fans love the club. It's a good period to be united and not divided. Historically Arsenal has been about that."

Arsenal travel to Middlesbrough, who are second from bottom, on Monday and will be hoping to get back into the top six by improving their record of one win in their last five league visits to the Riverside Stadium.